In conventional constructions using steel-pipe columns, there are cases in which beams made of H-shaped steel are connected. For connecting columns and beams, through diaphragms or inner diaphragms, which suit the height of the flange parts of the beams, are provided to transfer stress from the beams to the columns efficiently at their connection parts. A through diaphragm is a plate-like member that is connected between two columns by welding, whereas an inner diaphragm is a plate-like member that is connected inside the column by welding. Through diaphragms or inner diaphragms are usually connected in advance in factories.
As such a column-beam connecting structure, Patent Document 1 discloses a column-beam connection structure in which a column-beam connecting metal fitting is welded to a column. The metal fitting has a flat surface for at least an area of a peripheral face of the column that is to be connected with a beam, and a beam made of H-shaped steel is connected to a peripheral face of the column-beam connecting metal fitting by non-scallop welding.
Alternatively, there is a method in which outer diaphragms, which are connected to the outer faces of a column, are used (Patent Document 2, for example).